1. Field of the Invention
The present invention relates to devices for dermatology and more particularly to a skin resurfacing system that utilizes (i) a skin interface having a diamond fragment abrading surface for removing skin surface layers as the working end is translated over a patient""s skin, (ii) a source for delivery of a sterile fluids to the skin interface of the system; and (iii) an aspiration system for delivering fluids to and removing fluids and skin debris from the treatment site.
2. Description of Background Art
Dermatologist and plastic surgeons have use various methods for removing superficial skin layers to cause the growth of new skin layers (i.e., commonly described as skin resurfacing techniques) since the early 1900""s. Early skin resurfacing treatments used an acid such as phenol to etch away surface layers of a patient""s skin that exhibited damage which thereafter were replaced by new skin. (The term damage when referring to a skin disorder is herein defined as any cutaneous defect, e.g., including but not limited to rhytides, hyperpigmentation, acne scars, solar elastosis, other dyschromias, stria distensae, seborrheic dermatitus).
Following the removal of surface skin layers at a particular depth, no matter the method of skin removal, the body""s natural wound-healing response begins to regenerate the epidermis and underlying wounded skin layers. The new skin layer will then cytologically and architecturally resemble a younger and more normal skin. The range of resurfacing treatments can be divided generally into three categories based on the depth of the skin removal and wound: (i) superficial exfoliations or peels extending into the epidermis, (ii) medium-depth resurfacing treatments extending into the papillary dermis, and (iii) deep resurfacing treatments that remove tissue to the depth of the reticular dermis (see FIGS. 1A-1B).
Modern Techniques for skin layer removal include: CO2 laser resurfacing which falls into the category of a deep resurfacing treatment; Erbium laser resurfacing which generally is considered a medium-depth treatment; mechanical dermabrasion using high-speed abrasive wheels which results in a medium-depth or deep resurfacing treatment; and chemical peels which may range from a superficial to a deep resurfacing treatment, depending on the treatment parameters. A recent treatment, generally called micro-dermabrasion, has been developed that uses an air-pressure source to deliver abrasive particles directly against a patient""s skin at high-velocities to abrade away skin layers. Such a micro-dermabrasion modality may be likened to sand-blasting albeit at velocities that do not cause excessive pain and discomfort to the patient. Micro-dermabrasion as currently practiced falls into the category of a superficial resurfacing treatment.
A superficial exfoliation, peel or abrasion removes some or all of the epidermis (see FIGS 1A-1B) and thus is suited for treating very light rhytides. Such a superficial exfoliation is not effective in treating many forms of damage to skin. A medium-depth resurfacing treatment that extends into the papillary dermis (see FIG. 1B) can treat many types of damage to skin. Deep resurfacing treatments, such as CO2 laser treatments, that extend well into the reticular dermis (see FIG. 1B) cause the most significant growth of new skin layers but carry the risk of scarring unless carefully controlled.
It is useful to briefly explain the body""s mechanism of actually resurfacing skin in response to the removal of a significant depth of dermal layers. Each of the above-listed depths of treatment disrupts the epidermal barrier, or a deeper dermal barrier (papillary or reticular), which initiates varied levels of the body""s wound-healing response. A superficial skin layer removal typically causes a limited wound-healing response, including a transient inflammatory response and limited collagen synthesis within the dermis. In a medium-depth or a deep treatment, the initial inflammatory stage leads to hemostasis through an activated coagulation cascade. Chemotactic factors and fibrin lysis products cause neutrophils and monocytes to appear at the site of the wound. The neutrophils sterilize the wound site and the monocytes convert to macrophages and elaborate growth factors which initiate the next phase of the body""s wound-healing response involving granular tissue formation. In this phase, fibroblasts generate a new extracellular matrix, particularly in the papillary and reticular dermis, which is sustained by angiogenesis and protected by the reforming epithelial layer. The new extracellular matrix is largely composed of collagen fibers (particularly Types I and III) which are laid down in compact parallel arrays (see FIG. 1B). It is largely the collagen fibers that provide the structural integrity of the new skinxe2x80x94and contribute to the appearance of youthful skin.
All of the prevalent types of skin damage (rhytides, solar elastosis effects, hyperpigmentation, acne scars, dyschromias, melasma, stria distensae) manifest common histologic and ultrastructural characteristics, which in particular include disorganized and thinner collagen aggregates, abnormalities is elastic fibers, and abnormal fibroblasts, melanocytes and keratinocytes that disrupt the normal architecture of the dermal layers. It is well recognized that there will be a clinical improvement in the condition and appearance of a patient""s skin when a more normal architecture is regenerated by the body""s wound-healing response. Of most significance to a clinical improvement is skin is the creation of more dense parallel collagen aggregates with decreased periodicity (spacing between fibrils). The body""s wound-healing response is responsible for synthesis of these collagen aggregates. In addition to the body""s natural would healing response, adjunct pharmaceutical treatments that are administered concurrent with, or following, a skin exfoliations can enhance the development of collagen aggregates to provide a more normal dermal architecture in the skinxe2x80x94the result being a more youthful appearing skin.
The deeper skin resurfacing treatments, such as laser ablation, chemical peels and mechanical dermabrasion have drawbacks. The treatments are best used for treatments of a patient""s face and may not be suited for treating other portions of a patient""s body. For example, laser resurfacing of a patient""s neck or dxc3xa9colletage may result in post-treatment pigmentation disorders. All the deep resurfacing treatments are expensive, require anesthetics, and must be performed in a clinical setting. The most significant disadvantage associated with deep resurfacing treatments relates to the post-treatment recovery period. It may require up to several weeks or even months to fully recover and to allow the skin the form a new epidermal layer. During a period ranging from a few weeks to several weeks after a deep resurfacing treatment, the patient typically must wear heavy make-up to cover redness thus making the treatment acceptable only to women.
The superficial treatment offered by micro-dermabrasion has the advantage of being performed without anesthetics and requiring no extended post-treatment recovery period. However, micro-dermabrasion as currently practices also has several disadvantages. First, a micro-dermabrasion treatment is adapted only for a superficial exfoliation of a patient""s epidermis which does not treat many forms of damage to skin. Further, the current micro-dermabrasion devices cause abrasive effects in a focused area of the skin that is very small, for example a few mm2, since all current devices use a single pin-hole orifice that jets air and abrasives to strike the skin in a highly focused area. Such a focused treatment area is suitable for superficial exfoliations when the working end of the device is passed over the skin in overlapping paths. Further, such focused energy delivery is not well suited for deeper skin removal where repeated passes may be necessary. Still further, current micro-dermabrasion devices are not suited for deeper skin removal due to the pain associated with deep abrasions. Other disadvantages of the current micro-dermabrasion devices relate to the aluminum oxide abrasive particles that are typically used. Aluminum oxide can contaminate the working environment and create a health hazard for operators and patients alike. Inhalation of aluminum oxide particles over time can result in serious respiratory disorders.
The present invention comprises a hand-held instrument adapted for pain-free removal of skin layers in a treatment to induce neocollagenesis in the dermis to reduce wrinkles and alter the architecture of the dermal layers. A preferred embodiment of the inventive system comprises (i) a hand-held instrument with a resilient working skin interface that carries microscopic diamond fragments for abrading the skin surface in a controlled manner, (ii) a fluid source for supplying sterile fluids to the skin interface for cleaning skin debris from the skin interface; and (iii) a negative (xe2x88x92) pressure source for pulling fluid to the skin interface and thereafter aspirating fluid and skin debris from a treatment site.
More in particular, the working end that carries the resilient skin interface and sharp-edged diamond fragments is detachable from an intermediate instrument body and is inexpensive and disposable after being used for a single treatment. A preferred embodiment of hand-held instruments has a cartridge-type fluid reservoir that is detachable from the intermediate body section and is disposable. The working end defines a skin interface that engages and cuts or abrades the skin as it is translated across a treatment site. A preferred working end has a central channel and outflow aperture that communicates with a remote negative pressure source via a flexible tube. The skin interface is configured with a plurality of fluid inflow apertures generally about a perimeter of the skin interface. Preferably, the inflow apertures are located within a groove structure that allows substantial volume of fluid to be carried within the grooves and in contact with the treatment site. Intermediate to the arrangement of inflow and outflow apertures is a major portion of the skin interface that carries the diamond fragments, which range in diameter from about 10 xcexcm to about 250 xcexcm.
Of particular interest, the skin interface is formed of a resilient material such as silicone to allow the working end to flex and atraumatically engage the skin surface as it is translated across a treatment site. Also of particular interest, the suspension of the diamond fragments in resilient silicone seems to allow a slight movement or adjustment of the diamond fragments as the diamond abrasive architecture is translated over skin. In other words, the diamond fragments float to a some extent as they cut the skin surface and patients report that skin layer removals to a significant depth can be accomplished substantially without pain.
The aspiration source of the inventive system has multiple functions: (i) to draw the skin surface into a concave form of the skin interface and the diamond cutting architecture to perform the method of removing skin surface layers; (ii) to draw a sterile fluid across the diamond architecture to remove skin debris from the skin interface; and (iii) to further aspirate the skin debris and spent fluid volume to a remote collection reservoir.
In practicing a method of the invention, the following steps are performed, the system operator (i) places the skin interface carrying the abrasive architecture against the patient""s skin in a treatment site; (ii) actuates a negative pressurization source in fluid communication an arrangement of apertures in the skin interface to draw the skin into a concavity of the skin interface and against the abrasive architecture; (iii) translates the abrasive architecture across the treatment site to cut or abrade a skin surface layer; and (iv) contemporaneous with the cutting step, flowing a fluid (e.g., sterile water) generally about and across the abrasive architecture between the arrangement of inflow and outflow apertures in the skin interface under the negative pressures forces to (A) remove the skin debris and clean architecture; (B) to hydrate the skin to facilitate surface layer cutting, and (C) to cool the skin to make the skin treatment more pain-free.
In general, the invention provides a system and techniques for removing skin surface layers in a controlled manner.
The invention advantageously provides a technique to induce neocollageneis in a patient""s skin.
The invention advantageously provides a technique and system for rejuvenating a patient""s skin by surface layer removal to thereby induce the body""s wound healing response to cause noecollagenesis in the dermis of the treatment area.
The invention provides a system with a resilient skin interface that carries exposed sharp-edged diamond fragments for controlled cutting or abrasion of the skin surface.
The invention advantageously provides a system with a resilient skin interface that flexes to conform to the skin surface as it is translated across a skin treatment site.
The invention provides a working end in which sharp-edged diamond fragments are resiliently suspended in a flexible silicone.
The invention advantageously provides a fluid source for supplying a fluid to a perimeter of the skin interface to cool the skin, hydrate the skin and remove skin debris from the interface during use.
The invention advantageously provides an aspiration source communicating with a central aperture in the skin interface for drawing fluid across the skin interface to remove skin debris and aspirate such skin debris to a remote collection source.
The invention advantageously provides an instrument handle with a cartridge-type fluid reservoir that is removable and disposable.
The invention advantageously provides an injection-molded working end that carries diamond fragments that is inexpensive an disposable.
Other objects and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims. Additional advantages and features of the invention appear in the following description in which several embodiments are set forth.